182 JOHN E. S. MOORE. 



divisioual metamorphosis in the cells constituting the sperma- 

 tocytes of Helix, renders their homology with similar struc- 

 tures forthcoming in the cells of Vertebrates, of paramount 

 importance to those desirous of embracing under some more 

 general formula the numerous as well as heterogeneous life- 

 histories which constitute our knowledge of this subject. 



No one, so far as I am aware, has instituted any close 

 inquiry into the specific relationships existing between these 

 various " archoplasms," " spheres-attractives,^' and the appa- 

 rently often similar " Nebenkerns.^^ 



It is not, for example, generally recognised that if the 

 archoplasm, as figured by Hermann, has the relationships he 

 described in his work,^ or is equivalent to that apparently 

 similar outer portion of the " sphere- attractive" of van 

 Beneden and Boveri, the sphere, as it appears in a variety of 

 tissue-cells described in Flemming's works, differs in essential 

 parts from theirs. 



In Flemming's figures it is never represented as composed of 

 more than a simple radiation related to one or two central 

 bodies, with or without that immediate lighter zone, the " me- 

 dullary corpuscle" of van Beneden. The whole " sphere-attrac- 

 tive" of van Beneden and Boveri, however, always consists of 

 three distinct parts, an outer archoplasmic portion and inner 

 medullary corpuscle enclosing one or two central bodies, while 

 there is often present a prominent external radiation of the 

 whole cell-ma?s. Our knowledge of the specific relationships 

 between these various zones, bodies, radiations, and the similar 

 parts in the archoplasm (" Nebenkern") is in a most unsatis- 

 factory condition. 



It is not apparent whether the radiation about the central 

 bodies of Flemming- in tissue-cells and leucocytes is equivalent 

 to the archoplasmic portion of van Beneden's sphere, or to 

 its entirely external radiation. 



' ' Archiv fiir mikroskopisclie Anatomic,' vol. xxxvii, p. 575. 



'^ See riemming on the Leukocytes and the Attraktiouspharen of the 

 cell, in the 37tli volume of the ' Archiv fiir mikroskopische Anatomic ' 

 on Taf. xiv, pp. 274: — 287, and ligures. 



